Process of and apparatus for securing parts to rotor blade spars



Sept. 27, 1949. .J. T. PARSONS ETAL 2,483,230

PROCESS OF AND APPARATUS FOR SECURING PARTS TO ROTOR BLADE SPARS Filed May 3, 1946 2 Sheets-Sheet l JOHN 7." RMsoA/s' 52K Efieogzai @QM a Sept. 27, 1949. J. T. PARSONS ET AL 2,433,230

PROCESS OF AND APPARATUS FOR SECURING PARTS TO ROTOR BLADE SPARS Filed may '5, 1946 2 Sheets-Sheet 2 -three inches to eight inches.

Patented Sept. 27, 1949 PROCE'SS Q'F iAND 'APPAEATU S FOR SECUR- ING PARTS T0 ROTOR BLADESPARS John 3'1. ;P.arso ns ;and Erik R. sBrogren, sillraverse .City, Mich, assignors, by mesne assignments .to Parsons Corporation, .Detroit, Mich .a corporation of 'Michigan .ApplicationsMayB, 1946,.Serial N 0.661 210 '14 Claims. i

This invention relates to an improved process of and -,apparatus 'fonsecuring parts to and along the leng h o :a tubular el t b h ma hesion and particularly to such a processand apparatus for seouring .blade supporting parts 1 1053. rotor blade tubular I spar.

flheparticular process of ihermal adhesion em- ;ployed is .that oommonlyeknown in the trade as fgycle-welding. ;I t 'isa process wherein the adhesive .securement of the parts together is obtained by heating the adhesive in ,situ.

The tubular rotor blade spar :to which the parts are secured by-cyclewelding as here illustrated is a tapered tubular metal spar of the character used in a helicopter lrotor blade.

,The process and apparatus illustrated is one particulariy designed-to.secure;b1ade rib support- .ing hubs -or flange .by .cyclewelding to the spar .at predetermined positions. throughout its length and to obtain :such securement .Without resultin g. dislocation of the parts due to thegexpansion -,of the tubular spar .during the application of heat thereto .in the carrying -outof the cycle- .welding process. The fixture shown-is oneparlticularly designed to carry out .this process.

The spar illustrated v is .of substantial length and-this invention is adapted ,forsecurement of parts to a tube of substantial length. The rotor blade spar shown in one formhasa length of ,22 feet, a diameter at the hub of 2% inches an d.a

diameter at the tip of a -.of.an inch. The spar shown is'adapted to .be provided with a large number of ribs arranged in a.linear plane and adapted .to be secured to the spar by ,hub parts. It is not only necessary that these .hub parts .be securely mounted upon the spar but it isalso necessary that they be accurately positioned along the length of the spar. These hubparts are secured to the spar along itslength at :in- .tervals which may vary from between two .and As the spar is heated throughout its lengthto secure-these hub parts thereto by thermal adhesion .aspar of the length above stated .may expand :of :an inch or more in length.

An object of this invention is to secure parts by-thermal adhesion inaccurately spaced relationship along a tubular element without the parts becoming dislocated during the secure- -ment and to maintain the predetermined longi- 'tudinal spacing of the parts; along the-spar notwithstanding expansion lengthwise 'of the spar during the cyclewelding.

,Another object is to provide ;a process and fixturewhereby atubularspar provided with rib I hub parts which :are to be secured thereto is supported ;for the del'iveryaoi steam ,into ,one end of the spar to heat theadh-esive :to accomplish the .cyplewelcling of "the parts to the spar and wherein the arrangement iss lch that means are provided toso positiont h hub p rts during th cyclewelding process that while the parts ar Becpu a ely relativelyp s tionedalons .the spa-r they wi permit expansion of :thesp rline fly nd the influence of heat without disturbing the jpint termed bet een the hu par a d the spa o without d sturb n (t re a ve :lnca qp o h hub parts upon the spar.

A meritorious feature ;is that the hub parts .or flanges are so supported with respect to the tubular spar gtp which they are to be secured .by thermal adhesion that as the spar to which adhesion is madc'chfiinges its lengthwise dimenioneduring securementlof the par-ts thereto, the parts correspondingly change their linear positions while maintaining their relative positions. v During heating the zspar expands lengthwise. During cooling the spar contracts lengthwise. The ,hub parts are so supported that they cor.- .respondingly change their actual positions While maintaining -their "relative positions.

More-particularly an object is to provide a fixture.Whichincludesmeansfor supporting a tubular rotor .blade spar having hub parts mounted ,thereon and =means .for .delivering steam to .the :interior-ofsuch sparand means including. a similarly .positioned similar tubular ,frame spar .to which steam is alsodelivered which .frame spar :is provided -.with supports that position the hub :partsalong the rotor blade spar. .Due to thede- ,livery of steam both to the rotorblad-e spariand to the frame spar and dueto the sim'ilarposition- ;ing of these .lsirnilars pars their expansion and contraction linearlyqis equal ,and the vhub sup- ,portswcarriedby the frame spar which determine the position of thehub partsalong therotor blade spar therefore maintain their predetermined relative gpositions during the carrying outof .th-e cyc -welding pr ce s.

:Ihe fixture comprises a frame which includes ;a tubular frame ,spar which is similar to the tubular rotor vJolade .spar to which the hub parts :are -.to -be secured. This tubular frame spar .is

sion or rcontraction {under the influence of heat. tubular -frame-spar is provided with }a row of L-linearly spacedrhub part positioning rand spar supporting saddles. The rotor blade spar to which the hub parts are to be secured is disposed to extend along over these saddles and the hub parts which are to be secured to the rotor blade spar are positioned by the saddles. Means is provided to deliver steam to the interior of the rotor blade spar at the same time that steam is delivered to the frame spar so that the expansion and contraction lengthwise of the two spars will correspond.

Other objects, advantages and meritorious features of this invention will more fully appear from the following description, appended claims and accompanying drawings, wherein:

Figure 1 is a perspective of a fragment of the improved fixture showing a spar therein.

Figure 2 is a vertical sectional View, partly broken away, through one end of the fixture and spar.

Figure 3 is a side elevation, partly broken away, of a portion of the figure and spar.

Figure 4 is a vertical sectional view taken on the line 4-4 of Figure 3.

Figure 5 is a vertical sectional view taken on the line 5-5 of Figure 3.

Figure 6 is a vertical sectional view taken on the line 6-6 of Figure 2.

Figure 7 is a perspective of a fragment of a spar 52 showing a split hub part 58 clamped thereabout.

Figure 8 is a fragmentary section through one of the intercostal clamps enlarged as compared with Figure 5.

As hereinabove stated the purpose of this invention is to secure parts to and along a relatively long tube by thermal adhesion and to secure such parts to the tube in predetermined relationship. This is accomplished by assembling the parts upon the tube with heat responsive adhesive interposed between the tube and the parts and then heating the adhesive to cause the same to set and permanently secure the parts to the tube. The adhesive may be heated by heating the tube to which the parts are to be secured. The tube may be heated by introducing hot steam thereinto to flow therethrough.

Inasmuch as the tube will expand during heating and contract during cooling and in order that the parts may be secured to the tube in predetermined spaced relationship ,the parts are supported during the thermal adhesion upon supporting means which includes a second similar and similarly supported tube which second tube is heated simultaneously with and to the same degree as the first tube. The process and fixture herein described is designed to accomplish the above result.

The fixture includes a tubular base member ii] supported upon a plurality of fixed upright standards l2, one of which standards is shown in Figure l. A plate I4 is secured to and extends lengthwise along the tubular base member. A tubular member [8 extends along over the plate i4 and has one end clamped within the upright standard 56 which standard I6 is fixed to the plate M. Extending away from this fixed end this tubular member I8 is slidably supported at intervals upon a plurality of stationary saddle supports 28 fixed to the plate M. The tube 18 is free upon the saddle supports 20 so that as the tube is heated it may expand or contract lengthwise slidably over said saddle supports.

The plate 14 carries at one end, in proximity to the standard IS, an upright channel shaped standard 22. A steam pipe 24 extends through 4 this standard 22 as shown in Figures 1 and 2. This steam pipe communicates through a coupling 26 with the interior of the tubular member iii to introduce steam thereinto. This steam pipe is provided with a control valve 25. It receives its supply of steam from a steam main 28. ihis main 28 also supplies steam to a steam pipe 36 for discharge therefrom into a tubular spar 52 to which parts are adapted to be secured. The steam pipe 36 is provided with a control valve 29 and it communicates with the main 28 through a flexible conduit 21. This main 28 7 leads from a suitable source of steam not shown.

or r;

At the opposite end of the fixture a steam pipe 2 i-A, provided with a control valve --A is connected with the small end of frame spar 18 by a suitable coupling |8--A to lead steam therefrom to an outlet pipe 28A which returns the steam to the system. This return line 2BA is a flexible tube such as copper. A steam pipe 39A, having a control valve 29-A is coupled with the small end of the spar 52 by a suitable coupling 52-A and leads into this return line 28A.

The pipe 38 is adapted to be introduced into the open end of the tubular spar to which the parts are to be secured. For this purpose the pipe 39 is provided with means to form a tight internal joint with such spar. The pipe 30 is provided at its inner end with a conical end portion 32 (Figure 2). The outer end of the pipe is threaded as at 34 and there is rotatably threaded upon such outer end a manually operable wheel 36. Mounted upon the pipe 30 is a tube 40. This tube has a flange 38 upon its outer end which flange is engaged by the hub of the hand wheel 36 as shown in Figure 2. This flange 38 has a spline 31 received within a keyway 39 within the standard 22 to prevent rotation of the tube 40 while permitting its linear adjustment. The tube 30 has a pin 35 extending transversely therethrough. The outer ends of this pin are disposed within linear slots 33 in the tube 40 which prevents relative rotation between the tubes 30 and 40 while permitting limited relative linear movement.

The inner end of this tube 40 abuts a cone 42 which slidably encircles the pipe 39. Between the beveled face of this cone 42 and the beveled face of the end flange 32 are mounted a plurality of separate cylinder segments 44. These segments are held about the tube 39 by springs 46. These springs encircle the segments within grooves formed circumfercntially about the segments as shown in Figures 2 and 6. The ends of these cylinder segments 44 are beveled to correspond with the beveled faces of the end flange 32 of tube 30 and the cone 42 as shown.

It will appear therefore that when the wheel 35 is rotated to draw the tube 30 outwardly therethrough it will urge the segments 44 outwardly against the inner wall of the spar 52 to grip the same becaus the opposite ends of these cylinder segments bear against the cone 42 which cone is being simultaneously urged inwardly b the tube 30.

The gripping engagement of the segments 44 with the spar 52 holds the tube 30 within the spar against the steam pressure built up within tube 52. Reverse rotation of the hand wheel 36 loosens the segments from the spar 52. Safety stop pins 43 are removably provided within the standard 22 engaging the flange 38 on the end of tube 40 to prevent ejection of the same outwardly should the segments 44 accidentally release from the gasses?) .5 spar 2-. A gasket is interposed bet-ween the ehdfl'ange 32 and the ends or the cylinder segi nents 44" and is not only compressed therebetween when such segments are expanded radially but is also expanded radially toseal the joint formed thereby with the tubular spar 52 to prevent steam leakage.

"The spar here shown is illustrated as having-a huh mounting 54 illustrated in Figure2 as secured by pins such as is to the spar 5-2 against relative rotation. The standard 22 base. plate secured thereto. This plate 47 is provided with spaced apart pairs or cars 49 through which pins 5t extend as shown in Figures 1 and 2-. The hub 54- is provided with opposed radial flanges 53 whichare received between the ears Q'9.- Th -pins 51 extend through holes in the flanges securing the hub and through the hub the spar 52 to the standard 22.

The spar 52 extends linearly along and above the tubular frame spar E3, The spar 52 is the one to which the parts are to be secured. The s'D'a'r 52' which is here shown is a rotor blade spar fora helicopter rotor blade. Such spar is shown in Figure '3 as made up of a plurality of sections 55 di different diameter. Thes differeht diameter sections are die drawn from a uniform diameter tube so that the several sections 55 togetherconstitute an integral spar tapering by steps from one end to the other.

The fixture is so constructed that the frame tube or spar i8 is a "duplicate of the live spar to whieh the parts are to be secured. The spar 58 carries at intervals along its length a series of supporting elei'nen'ts orsaddles 55. These saddles are forked at their upper ends as at 5 that the live spar 52 can extend therethrough but is free therefrom. a rose saddles 58 are each "crevices with a locating pm 66 adapted to position a hub part 58 thereon. Each hub part is mounted u on the live spar 52 and is provided with apertures 59. The locati ng'pi'n 5s extends through one of these apertures 59 and. also extends through an aperture through the saddle 56 as shown in Figure 4 to position the hub part '58. These locating pins to hold the hub parts 58 positioned on the saddles during the secure nent h'fthe hub parts to the live spar 52.

Each but; part of rib supportingflange 58 is here shown as having a split cylindrical collar 58-=-A 'or split hub proper mounted upon the spar 52. This collar dii A is encircled by a clamping band 64 which clamps the split hub portion'tigha 1y around the spur as shown particularl in Figure 7.

In addition to the hub parts 58 being secured to the spar 52, wood strips or blocks termed intercostals were also secured at spaced intervals to the spar 52. The fixture is provided with suitabl clamping mechanism to hold these intercostal's to the spar during their adhesive securement thereto. Such clampin mechanism is carried by supporting rods 7? which'rods are carried by the saddles 56 and extend lengthwise of the frame spar l8. Two such rods lll'are shown.

These rods extend through provided apertures in the saddlesfit. These rods may be secured to one ofthe saddle-elements but have permitted slidable adjustment through the remaining saddles.

' V 'A plurality of clamping devices are supported ment for ten minutes at 280 F to one upright section 14 andis adapted tobe swung down and reccivedwi-thinthe forked upper end of the other upright section 14-. The-free end of the top cross piece 16 is threaded and a hand nut 18 is threaded thereupon as shown in Figure 5. The hub of this hand n'ut-may' be tightened against the adjacent upright section II to draw the two upright sections down upon the intercostals 69 holding them snugly against-the spar.

Each upright section T4 of theclampinghqecm anism is provided with=a rabbeted block 80, shown in Figures 5 and 8, which block may be provided with a compressible facing 82 formed of rubber or the like. A pointed retainer pin 84 may be mounted in the block 8!) to project. through the compressible facing 82 toengage an intercostai member 69 tohold it in position upon the block "as and against the spar 52' as shown in Fig ure 8.

Figure 1 shows the fixture provided with a standard 86 upon which is pivoted an offset lever 83 which is adapted to swing downas shown in Figure 1 to engage within a slot formed in-apart at mounted upon the spar 52 to rotatably--posi-- tion suchsparj This lever may beswungu-p-to release the'spar.

In "carryin out the instant process the spar 52 to which the hub-parts '53 are to be secured andthe'hub parts 53 themselves-are-first treated with a suitable thermal adhesive. Intheparticular cycleweldin'g process which has been commercially employed this adhesive'coati ngie-commercially known by the trade designation 0- 3. It is a heat responsive plastic adhesive. plastic coating may be painted upon the entire outer surface of the spar and overthe inner surfaces of the collars or the'hub parts 5'8--A. Such coated surfaces may then be allowed' tofair' dry for 24 hours or may be subjected lio'halftlfeat Following this preliminary preparation the'hub parts 58 are then placed upon the spar 52 and the inner surfaces ofthe collars 58-A of the hub parts are coated with the second coating employed in the cyclewelding process. This second coating has the trade name designation 0-3-4. Those portions-of the span 5'2 "which-are to be embraced by the collars of the hub-parts 58 are also coated with this second coating. In exaggerated thickness these coatings are shown in Figure 4 as a layer 92. The spar 52 with the hub parts supported thereon is then pos'itionedwithi n the fixture as hereinabove set forth. The steam lines 3:] and 30A are connected-with opposite ends of the spa-r "as hereinabove described This particular invention concerns itself with the fixture and iviththe process involved in this sec.- ond step of the cyclewelding method.

Steam is then introduced from a suitable source of steam supply into the main 28 which supplies steam to the steam'pipes 24 and 36 which pipes deliver steam into the tubular frame spar m "and the tubular live spar '52. Steam is delivered into these-spars sc' asto heat the spars simultaneously and equally so that'they will expand simultaneously and equally. Ihe spar 52 is heated to that temperature which is required to permanently set the adhesive which depends uponthe particular heat responsive adhesive used. Such temperature with the cyclewelding coating 043-4 is in the neighborhood of 350 F. and is continued for twenty minutes or thereabouts. Thesteam flows through both spars. being discharged therefrom throughsteam returnllines z-eniand Sit-A into outlet 28--A,

During the heating of the spar 52 it tends to expand lengthwise. The framespar which receives steam at the same temperature, as it is from the same source, and which is a spar similar to spar 52 to which the parts are being secured tends to similarly expand lengthwise. The saddles 56 which carry the hub parts travel with the frame spar and continue to maintain these hub parts at the proper location and at the same relative points alon the spar 52.

What we claim is:

1. A fixture for securing parts upon and along the length of a tubular spar comprising, in combination, a frame base provided with a line of spar supports, a tubular frame member supported at one end upon the base and seated at intervals along its length upon said spar supports for slidable extension thereover, said tubular frame member provided at intervals along its length with a row of upright supports for spar parts to be secured to a tubular spar extending along said row.

2. A fixture for securing parts upon and along the length of a tubular element, comprising, in combination, a frame including a base provided with a line of upright supports for a tubular element, a tubular frame element secured at one end to the base and slidably seated along its length uponsaid supports, said frame element provided at intervals along its length with a row of upright saddle supports for parts to be secured to a tubular spar extending along said row and a source of steam having one line leading into the tubular frame element and a second line adapted to lead into a tubular element extending along said supports.

3. A fixture for securing parts upon a tube, comprising, in combination, a frame including a tubular member supported at intervals throughout itslength for permitted linear expansion, said tubular member provided with a row of linearly spaced upright part supporting devices and a steam line leading into said tubular member.

4. A fixture for securing spar parts upon a tubular spar comprising, in combination, a frame including a tubular spar fixed at one end and supported at intervals throughout its length toward its opposite end for linear expansion, said frame spar provided with a row of linearly spaced apart upright spar supporting saddles, a standard to which one end of a tubular spar is adapted to be secured, said standard fixed on the frame at one end of and in line with said row of saddles so that a spar secured to said standard will extend over the saddles.

5. A fixture for positioning parts upon and along a tubular spar comprising a frame including a tubular spar fixed at one end and supported at intervals throughout its length spaced away from said end for linear expansion, said frame spar provided with a row of linearly spaced apart spar part supporting and positioning members and means for heating the tubular spar.

6. A fixture for assembling spar parts upon a tubular spar comprising a frame including a tubular spar fixed at one end and supported at intervals throughout its length spaced away from said end for linear expansion, said frame spar provided with a row of upright linearly spaced apart spar part supporting and positioning members and means for introducing steam into said frame spar.

'7. A fixture for assembling spar parts upon a tubular spar comprising a frame including a tubular spar fixed at one end and supported at intervals throughout its length toward its opposite end for linear expansion, said frame spar provided with a row of linearly spaced apart upright spar part supporting and positioning members, a fixed standard disposed at one end of the row of members and adapted to support one end of a tubular spar extending over said members and a steam line adapted to deliver steam to said frame spar and to the spar extending over said members.

8. A fixture for assembling spar parts upon a' tubular spar comprising a frame provided with a tubular spar supported at intervals throughout its length for linear expansion, said frame spar provided with a row of linearly spaced apart upright spar supporting members, spar part positioning means carried by said members, a standard fixed at one end of the row of members adapted to support one end of a tubular spar extending over said members.

9. A fixture for assembling spar parts upon a tubular spar comprising a frame provided with a tubular spar supported at intervals throughout its length for linear expansion, said frame spar provided with a row of linearly spaced apart upright spar supporting members, spar part positioning means carried by said members, steam delivery means at one end of the row of members adapted to deliver steam to a spar extending over said members and adapted to deliver steam to the frame spar which carries the members.

10. A fixture for assembling rotor blade parts upon a tubular rotor blade spar comprising a frame provided with a tubular spar supported at intervals throughout its length for linear expansion, said frame spar provided with a row of linearly spaced apart upright rotor blade spar supporting members, blade part positioning means carried by said members, clamping means mounted upon said frame spar between said members operable to hold parts against the tubular spar which extends over the members and means for introducing steam into said frame spar and the rotor blade spar mounted upon said suporting members,

11. That process of securing a plurality of rotor blade parts at determined positions to and along a tubular rotor blade spar by thermal adhesion comprising supporting the spar, while provided with blade parts mounted thereon and carrying interposed thermal adhesive, for linear expansion under heat; providing a corresponding and parallel frame spar similarly positioned and similarly supported for linear expansion under heat, said frame spar provided with blade part supports spaced linearly therealong; positioning the blade parts along the rotor blade spar by mounting them upon the blade part supports on the frame spar to shift therewith upon linear expansion of the frame spar and heating the rotor blade spar and frame spar simultaneously and substantially equally for substantially simultaneous and equal expansion and sufficiently to set the adhesive securing the blade parts to the rotor blade spar.

12. That process of securing a plurality of blade parts at determined positions to and along a tubular rotor blade spar by thermal adhesion comprising supporting the spar, while provided with blade parts mounted thereon and carrying thermal adhesive between the spar and the parts, for linear expansion under heat; providing a similar frame spar similarly positioned and supported in adjacent parallelism for corresponding linear expansion under heat, said frame spar having blade part supports fixed thereto and spaced linearly therealong; positioning blade parts along the rotor blade spar by securing them to the blade part supports on the frame spar to shift therewith upon linear expansion of the frame spar, delivering steam to the interior of the rotor blade spar and the interior of the frame spar to simultaneously and equally heat said spars for substantially simultaneous and equal expansion and sufiiciently to set the adhesive securing the blade parts to the rotor blade spar.

13. That process of securing by thermal adhesion a plurality of parts to and along a tubular element comprising supporting the tubular element for linear expansion under heat, holding said parts spaced along said tubular element by positioning them along a second tubular element supported for linear expansion under heat, and heating said two tubular elements simultaneously.

14. That process of securing by thermal ad- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,297,643 Boyer Mar. 18, 1919 20 2,284,563 vDillman et al. May 26, 1942 

